<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        /* 容器 */
        .div-big {
            /* 设置外层元素的弹性布局 */
            display: flex;
            /* 主轴方向 */
            /* flex-direction: column-reverse; */
        }
        .div01 {
            background-color: red;
            /* 当前元素占据的份数 */
            flex: 2;
            order: 1;
        }
        .div02 {
            background-color: yellowgreen;
            flex: 2;
            /* order 排列顺序，从下到大 */
            order: 0;
        }
        .div03 {
            background-color: burlywood;
            flex: 1;
            order: 2;
        }
        .div04 {
            background-color: pink;
            flex: 1;
            order: 3;
        }
    </style>
</head>
<body>
    <div class="div-big">
        <div class="div01">div1</div>
        <div class="div02">div2</div>
        <div class="div03">div3</div>
        <div class="div04">div4</div>
    </div>
</body>
</html>